How to read LoRa Messages in Serial monitor via heltec esp32

Question

I am new to the esp32 and LoRa messaging.

I am following the two examples in the heltect esp32 lora library.

The two modules I am using to send and receive data have an oled display... and I print their values to the serial monitor. The data values appear on the oled display but they are random characters in the serial monitor like this... "⸮⸮3⸮⸮JS⸮ ⸮⸮⸮⸮J)⸮⸮".

My question is how can I receive data from the sender in string/float/integer like form so I can perform logic on them. I am new to c++ and lora so any help is welcome.

I am pretty sure this(the first code block directly below this paragraph) is the piece of code responsible for printing the received message, but it is not printing in any type of format I can work with even when I change the "char" dtype to String.

while (LoRa.available()) {
  Serial.print((char)LoRa.read());
}

Receiver Code

/* 
  Check the new incoming messages, and print via serialin 115200 baud rate.
  
  by Aaron.Lee from HelTec AutoMation, ChengDu, China
  成都惠利特自动化科技有限公司
  www.heltec.cn
  
  this project also realess in GitHub:
  https://github.com/Heltec-Aaron-Lee/WiFi_Kit_series
*/

#include "heltec.h"

#define BAND    915E6  //you can set band here directly,e.g. 868E6,915E6
void setup() {
    //WIFI Kit series V1 not support Vext control
  Heltec.begin(true /*DisplayEnable Enable*/, true /*Heltec.LoRa Disable*/, true /*Serial Enable*/, true /*PABOOST Enable*/, BAND /*long BAND*/);

}

void loop() {
  // try to parse packet
  int packetSize = LoRa.parsePacket();
  if (packetSize) {
    // received a packet
    Serial.print("Received packet '");
    // read packet
    while (LoRa.available()) {
      Serial.print((char)LoRa.read());
    }
    // print RSSI of packet
    Serial.print("' with RSSI ");
    Serial.println(LoRa.packetRssi());
  }
}

Sender Code

    /* 
  Basic test program, send date at the BAND you seted.
  
  by Aaron.Lee from HelTec AutoMation, ChengDu, China
  成都惠利特自动化科技有限公司
  www.heltec.cn
  
  this project also realess in GitHub:
  https://github.com/Heltec-Aaron-Lee/WiFi_Kit_series
*/
#include "heltec.h"
#define BAND    915E6  //you can set band here directly,e.g. 868E6,915E6

int counter = 0;

void setup() {
  
  //WIFI Kit series V1 not support Vext control
  Heltec.begin(true /*DisplayEnable Enable*/, true /*Heltec.LoRa Disable*/, true /*Serial Enable*/, true /*PABOOST Enable*/, BAND /*long BAND*/);

  
}

void loop() {
  Serial.print("Sending packet: ");
  Serial.println(counter);
  // send packet
  LoRa.beginPacket();
/*
* LoRa.setTxPower(txPower,RFOUT_pin);
* txPower -- 0 ~ 20
* RFOUT_pin could be RF_PACONFIG_PASELECT_PABOOST or RF_PACONFIG_PASELECT_RFO
*   - RF_PACONFIG_PASELECT_PABOOST -- LoRa single output via PABOOST, maximum output 20dBm
*   - RF_PACONFIG_PASELECT_RFO     -- LoRa single output via RFO_HF / RFO_LF, maximum output 14dBm
*/
  LoRa.setTxPower(14,RF_PACONFIG_PASELECT_PABOOST);
  LoRa.print("hello ");
  LoRa.print(counter);
  LoRa.endPacket();
  
  counter++;
  digitalWrite(25, HIGH);   // turn the LED on (HIGH is the voltage level)
  delay(1000);                       // wait for a second
  digitalWrite(25, LOW);    // turn the LED off by making the voltage LOW
  delay(1000);                       // wait for a second
}

Answer 1

Perhaps, the serial monitor is configured with the wrong Baud Rate? In my case, default in IDE was 9600, but ESP32 sent with 115200. You can change the Baud Rate in a combobox in the serial monitor.